Wireless communication systems are known to include a communication resource allocator, a plurality of communication units, a plurality of communication resources, and repeaters. The communication units may be mobile units which are mounted in vehicles, portable units which are carded about by the person, or cellular telephones.
Due to the size of most communication units, they are often misplaced and/or are subjected to being stolen. When a communication unit is stolen, the person in possession has access to the communication system. This situation is further worsened when the communication unit is a secure communication unit and the encryption key and algorithm were programmed into the radio. Thus the person in possession of the stolen unit would be able to listen to secure communications. This scenario is further worsened when the communication unit is that of a police officer or fire department personnel. In these situations, the person in possession of the radio can monitor police activity or disrupt police activity by transmitting via the communication unit.
In a large metropolitan area, it is estimated that at least one communication unit is stolen from a policeman each day. This presents a significant problem to the operators of the communication system. Such a problem allows less than scrupulous people access to the police channels and as mentioned above could disrupt service. In addition, a stolen radio may be reverse engineered and subsequently used on the system. Therefore, a need exists for detecting and preventing access to a wireless communication system by an unauthorized or stolen communication unit.